Another iteration of our “eye observation” open-hardware

Our goal is to get objective feedback about eye position and behaviour, which requires some sort of eye tracking.  A decent eye-tracking headset costs anywhere between $400  and $10,000 dollars…  which is just too much for the majority of the world who earn less than $10 a day. So, lets make it affordable!

Continue reading “Another iteration of our “eye observation” open-hardware”

Hackademy – hacking Google Cardboard V2

Rather than implementing a new VR Headset for EyeSkills, could we push the price-point down even further, by hacking the standard Google Cardboard V2 design?  That’s one of the questions we explored last weekend at Careable’s first Hackademy!

The standard design has a capacitive button which touches the screen as user input when the user depresses an “origami” lever on the right upper side:

In the manufacturer’s schematics it becomes clear that this is a separate unit…  so after pulling it apart…

…we figured, why not replace this with a new core capable of supporting on-device eye tracking?  Here’s the first mockup.  The tabs at the bottom represent the cameras, the fuzzy tubes are cables, the yellow foam blocks are the USB connectors, and the purple block is the USB hub (all to correct size).

This could be folded back into the existing headset to give us just what we need!

I’m now moving towards programming a parametric model of this interior component which we can prototype using the Hacker Space’s laser cutter.  Very much looking forward to going back there this weekend!!!

At the same time, other members of the group have been exploring how to modify a standard v2 cardboard to improve both the ergonomics and reduce stray light entering the viewing area (after all, people’s foreheads and noses vary more than you might realise until you start looking closely!!!).

Here we are in Potsdam’s wonderful little Maker Space…

And here are some of the wonderful team explaining what we’re doing to members of other teams at the Hackademy….

It was an inspiring weekend, but 7am starts and getting back to bed at midnight after solid work three days in a row have taken their toll a little!

Eleksmaker A3 Laser Cutter

So, I’m still trying to get the Eleksmaker A3 laser cutter to work as I need.

So far, I’ve come to the conclusion that the original version of GRBL installed on the cheap Arduino nano board the “Mana” board comes with, is just no good.  I’ve flashed it to v1.1 :

brew install avrdude

avrdude -c arduino -b 57600 -P /dev/cu.wchusbserial1420 -p atmega328p -vv -U flash:w:grbl_v1.1f.20170801.hex

Then I found LaserWeb for OSX, configured it, and had the print head slamming against the side of the case.  It took me a while to work out that all my axes were inverted. After swapping the X-Axis carriage around, I was still left with an  inverted y-axis, which I solved by sending $3=2 as GCODE to the board via the console in LaserWeb ($3=2 means invert the y-axis, where $3=1 would mean inverting the x-axis).

The next problem was that the “cuts” were three times larger than they ought to be.

The next secret is hopefully to send this set of gcode instructions to the board to configure the number of steps/mm correctly….

$0=10 ;Step pulse, microseconds
$1=100 ;Step idle delay, milliseconds
$3=2 ;Y axis direction inverted
$10=0 ;send work coordinates in statusReport
$30=255 ;max. S-value for Laser-PWM (is referenced to the LaserWeb PWM MAX S VALUE)
$31=0 ;min. S-value
$32=1 ;Laser Mode on
$100=80 ;steps/mm in X, depending on your pulleys and microsteps
$101=80 ;steps/mm in Y, depending on your pulleys and microsteps
$102=80 ;steps/mm in Z, depending on your pulleys and microsteps
$110=5000 ;max. rate mm/min in X, depending on your system
$111=5000 ;max. rate mm/min in Y, depending on your system
$112=2000 ;max. rate mm/min in Z, depending on your system
$120=400 ;acceleration mm/s^2 in X, depending on your system
$121=400 ;acceleration mm/s^2 in Y, depending on your system
$122=400 ;acceleration mm/s^2 in Z, depending on your system
$130=390 ;max. travel mm in X, depending on your system
$131=297 ;max. travel mm in Y, depending on your system
$132=200 ;max. travel mm in Z, depending on your system
$$ ;to check the actual settings

If I type $$ I see that $100 is currently set to 250, which is certainly close to the 3X I’m seeing… So, let’s see how far this takes us…

Yes. Lovely. $110 and $111 are the pivotal instructions.

http://itink.it/wiki/doku.php?id=en:tinkering:laser:eleksmakera3pro

Sadly… The next problem seems to be that 2.5w just isn’t enough.  I can’t get through 1mm card at 100% power only cutting 250mm per minute!

I’ll have to organise some test files to see which speeds/power ratios/repetitions work best.